Saved Bookmarks
| 1. |
The size of the image of an object which is at infinity as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from convex lens, find new size of image : |
|
Answer» 1.25 cm `- (1)/(u) + (1)/(v) = (1)/(f)`  `- (1)/(4) + (1)/(v) = (1)/(-20)` v = 5 cm `m = (v)/(u) = (5)/(4) = 1.25` `m = (I_(2))/(I_(1)) = (I_(2))/(2) "" therefore I_(2) = 2 xx 1.25 = 2.5 cm`. |
|